policy-statement and from rib matching

Hi,

Is there a reason this policy doesn't work?

prefix-list routes-from-main {
1.1.1.0/24;
}

policy-statement accept-from-main {
term ok {
from {
rib inet.0;
prefix-list routes-from-main;
}
then accept;
}
term reject-rest {
then reject;
}
}

Basically I wanted to import a route from inet.0 to another routing instance.

Importing routes from a routing instance to another instance (or even inet.0) works with from instance statement:

prefix-list routes-from-test-vr {
    1.1.1.0/24;
}
policy-statement accept-from-test-vr {
    term ok {
        from {
            instance test-vr;
            prefix-list routes-from-test-vr;
        }
        then accept;
    }
    term reject-rest {
        then reject;
    }
}

test2-vr {
    instance-type virtual-router;
    interface lo0.1;
    routing-options {
        instance-import accept-from-test-vr;
    }
}

What does from rib statement match anyways, and how does it compare to from instance matching?

Is there a way to make from rib statement work or i'll have to resort to rib-groups?